Psychoendocrine responses to bicycle exercise in healthy men in good physical condition.

Blood levels of cortisol, prolactin, somatotropin, dopamine, noradrenaline, adrenaline, and lactate were analyzed in 18 healthy men in good physical condition in four repeated bicycle exercise tests. Profiles of pituitary hormone secretion into blood varied intra- and interindividually from one test to another, even though the work load remained unchanged. Catecholamine and lactate levels regularly increased during each exercise test. A factor analysis of the endocrine responses supports the assumption that pituitary hormones respond to psychological state factors while catecholamines and lactate increases are related to physical load.